The conditions that cause swelling of the back of the feet in the elderly are divided into physiological and pathological causes, and the common causes are as follows: 1. physiological: including swelling of the back of the feet caused by tight shoes and socks, swelling of the back of the feet caused by sitting or standing for a long time, and swelling of the back of the feet caused by taking drugs, such as calcium antagonist antihypertensive drugs can cause swelling of the feet, and the symptoms of swelling of the feet can be relieved after stopping the use of drugs; 2. pathological: common are heart failure, hyperthyroidism The swelling of the feet can be relieved after stopping the drugs. The main underlying diseases of heart failure include hypertension, coronary heart disease, etc. The swelling is a slow process at this time. The swelling usually appears first on the back of the foot or ankle, disappears when you wake up, and becomes more pronounced at night. Without control or intervention, the swelling will become more and more pronounced, gradually shifting from the dorsum of the foot or below the ankle to the ankle or lower extremity. Low thyroid function can also cause swelling of the back of the foot, and low protein and reduced albumin can cause swelling of the back of the foot or ankle. 3. Drug causes: Among the antihypertensive drugs, diphenhydramine can cause gradual swelling of the lower limbs. Of course, the patient should take the medication, and other causes should be excluded before considering that it is caused by medication.